The privacy acquired in the liquid network when performing pegin and pegout seen from the point of view of a third party observer is very similar to that of a mixer, your coins enter a federation pool and are mixed with others since consolidations are performed and when you perform the pegout you do not know whose coin it is.
The histories of all the coins are mixed. An advantage over coinjoin is that it leaves no trace in the chain, beyond the fact that you could know all the addresses of the federation and mark them.